<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .shadow{
        float:left;
        margin-left:20px;
        background: #EEFF99;
        width:200px;
        height:400px;
        }

        .shadow:hover{
             -webkit-box-shadow: #ccc 0px 10px 10px;
             -moz-box-shadow: #ccc 0px 10px 10px;
             box-shadow: #ccc 0px 10px 10px;  
        }
    </style>
</head>
<body>
    <div class="shadow"></div>
    <div class="shadow"></div>
    <div class="shadow"></div>
    
</body>
</html>